Hi Casandra!
I have taken both my kids to Disney World BEFORE their 1st birthday! So, your son will definitely have a good time!
One of my favorite things for kids this age is any show or parade. There is always so much color, lots of characters and great music. I have a distinct memory of watching my 7 month old son stare at Festival of the Lion King...he was looking at Simba, but I was looking at him!
Some gentle rides he should like are Small World, Peter Pan (Magic Kingdom) and The Seas with Nemo and Friends (Epcot). If he's familiar with the shows on Disney Jr, he will love Disney Jr LIVE at Hollywood Studios.
Don't forget to check out the
Magical Beginnings Map--it highlights all the attractions designed for the preschool set. You can print it out at home and show it to him!
Also, this isn't an attraction, but there are Baby Care Centers in each park--with private nursing rooms, changing tables, a TV, books, highchairs and more. You'll want to check those out for sure!